Radius gauges, also known as fillet gauges or radius templates, are tools used to measure or replicate the radius or curvature of curved surfaces or edges. They are commonly used in various industries such as automotive, woodworking, metalworking, and engineering. Radius gauges are particularly useful for checking and verifying the radius of existing curves or for transferring radius dimensions from a reference to the workpiece. Here's an overview of radius gauges:

1.      Design and Construction: Radius gauges typically consist of a set of individual blades or leaves, each having a specific radius size or curvature. The blades are arranged in a fan-like manner, with each blade labeled with its corresponding radius value. The blades are often made of durable material, such as stainless steel, and are attached to a pivot or hinge mechanism for easy opening and closing.

2.      Measurement and Replication: To use a radius gauge, the user selects the appropriate blade that closely matches the curvature of the surface being measured or replicated. The blade is then placed against the curved surface, and the user checks for a proper fit. If the blade fits snugly without gaps or overlaps, it indicates that the radius of the surface matches the radius of the selected blade. If none of the available blades match perfectly, the user may select the closest one and record the difference for further adjustment or replication.

3.      Types of Radius Gauges: Radius gauges are available in different sets, offering a range of radius sizes. Some sets may have a limited number of blades, while others provide a broader range of radius options. Additionally, there are specific types of radius gauges designed for particular applications, such as automotive bodywork, woodworking, or tool and die making.

4.      Fillet Radius Measurement: In addition to measuring convex radii, radius gauges can also be used to measure concave fillet radii. For concave measurements, the blade is placed inside the fillet or recessed area, ensuring a proper fit along the curve.

Radius gauges are handy tools for ensuring the accuracy of curved surfaces and maintaining consistent radii in various applications. They are commonly used in tasks such as checking the radius of rounded edges, matching curves for machining or fabrication, inspecting mold and die work, and verifying the dimensions of machined parts. With their compact and versatile design, radius gauges provide a convenient and reliable method for measuring and replicating radii.